0.46% unipolar strain in lead-free BNT-BT system modified with Al and Sb

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.935Ba0.065Ti1-x(Al0.5Sb0.5)xO3 (BNBT6.5-xAS) were prepared by a conventional solid sintering technique and their structure and electrical properties were systematically investigated. With increasing AS content, BNBT6.5-xAS ceramics underwent a phase transition from ferroelectric to relaxor phase, accompanied with the significant disruption of ferroelectric order. Accordingly, the ferroelectric-relaxor transition temperature TF-R was shifted down to room temperature, and thus a large unipolar strain of 0.46% (at 80 kV/cm) corresponding to a large signal d33*of 573 pm/V is obtained in 1.5 mol% AS-modified samples.